1. Field of the Invention
The present invention relates to work machine, such as a tractor, wheel loader, or backhoe that is provided with a diesel particulate filter (DPF).
2. Description of the Related Art
In order to mitigate and address recent environmental issues, regulations concerning gas emissions from diesel engines and the like have become more stringent. In the field of work vehicles such as agricultural machinery and construction machinery as well, various techniques for reducing particulate matter (PM) included in gas emissions. have been developed in order to comply with such gas emission regulations.
Typically, a diesel engine is furnished with a gas emission cleaning system for trapping particulate matter included in gas emissions. In a gas emission cleaning system, gas emissions are passed through a diesel particulate filter (DPF) furnished in the interior, to trap the particulate matter. The trapped particulate matter accumulates in the DPF of the gas emission cleaning system, and therefore the DPF must be regenerated to eliminate the particulate matter in an appropriate manner, so that the DPF does not gradually give rise to clogging and to a high level of air resistance in the exhaust system.
Such a technique relating to regeneration of a DPF is the DPF system disclosed in Japanese Laid-Open Patent Application 2011-256845, for example.
The DPF system disclosed in Japanese Laid-Open Patent Application 2011-256845 is provided with: a diesel particulate filter connected to the exhaust pipe of a diesel engine, and comprising a filter for trapping PM in exhaust gases, and an oxidation catalyst furnished to the upstream side of the filter; and temperature sensors respectively furnished to the upstream side and downstream side of the oxidation catalyst. In this DPF system, when the amount of accumulated PM in the filter exceeds a given amount, regeneration of the diesel particulate filter is performed, with the temperature detected by the temperature sensor at the upstream side of the oxidation catalyst set at or above a first threshold value, and the temperature detected by the temperature sensor at the downstream side of the oxidation catalyst set at or above a second threshold value. When a malfunction of the temperature sensor at the upstream side of the oxidation catalyst has been detected, the second threshold value is modified upward.